Surface coatings such as monocoat, clearcoat/colorcoat, and tricoat are favored for the protection and decoration of substrates such as vehicle bodies. The surface coatings can utilize one or more pigments or effect pigments to impart the desired color or appearance, such as solid, metallic, pearlescent effect, gloss, or distinctness of image, to the vehicle bodies. Metallic flakes, such as aluminum flakes are commonly used to produce coatings having flake appearances such as texture, sparkle, glint and glitter as well as the enhancement of depth perception in the coatings imparted by the flakes.
Repair of such coatings that have been damaged, e.g., in a collision or stone chipping or scratches, has been difficult in that a vehicle repair body shop or a refinisher may have to go to great lengths to repeatedly try out and to locate a best aftermarket refinish coating composition that matches the color and appearance of the vehicle's original coating, also known as original equipment manufacturing (OEM) coating. While each coating composition used in a vehicle's original coating is manufactured to a given color standard, so that, in theory, all vehicles painted with a given coating composition should appear the same color and appearance, due to a host of different variables, such as changing atmospheric conditions and use of different application techniques, the appearance of a given coating composition may actually vary from plant to plant and over different times of any year. Consequently, vehicles manufactured at one plant may appear a different color than vehicles painted with the same coating composition at another plant. A number of refinish matching coating compositions must therefore be developed for each OEM coating composition. Presently there is no quick, easy and inexpensive way to determine which aftermarket matching refinish coating composition is the best match in color and appearance for a particular OEM coating.
Various color matching techniques have been developed in the past to aid the selection of the correct matching coating composition to refinish a vehicle, but all suffer from certain significant limitations. For instance, visual tools such as refinish color chips have been used on many occasions to find a suitable match for the vehicle that needs refinishing. However, visual color matching is time-consuming, cumbersome and subject to many errors as a result of poor lighting conditions, operator variances, or variation to the original standard by the paint manufacturer. Another method involves the use of vehicle data, such as its make, model year and manufacturer's paint code. The paint code is used to identify all the different aftermarket refinish matching coating compositions and corresponding coating formulas created for that paint code. Additional information further defining the matching coatings resulted from the matching coating compositions is associated to each formula which helps the refinisher define which is the best match for the vehicle of that make and model year in question. Such information is gathered from a number of sources and resides in either electronic or printed formats. Accessing such a bank of information is very time-consuming and does not always lead to the correct coating match.
A further method commonly employed involves the use of a computer controlled colorimeter or spectrophotometer which measures the color values of an undamaged area of the coating on the vehicle and compares these color values stored in a database that contains color data for various refinish matching coatings and corresponding matching formulas. From that comparison, the computer locates one or more preliminary matching formulas for the vehicle's original coating color and appearance within an acceptable tolerance. An example of such method was disclosed in U.S. Pat. No. 7,145,656. Said method, however, requires measured color values and cannot identify matching formulas based on vehicle identification information.
An even further development is to use both the measured color values and vehicle identifying information to locate potential preliminary matching formulas from a refinish matching coating database. One example of such method was disclosed in U.S. Pat. No. 6,522,977. In such method, sample coatings resulting from each of the preliminary matching formulas are prepared and test sprayed. Color match is then visually determined. In most cases, the preliminary matching formulas need to be adjusted manually and repeatedly by trial and error until a match is achieved.
Thus, a continuing need still exists for a method to select one or more matching formulas to match color and appearance of an article, and particularly, to match the coating of a vehicle that needs refinish, with minimum requirement for repeated testing, manual adjustment and trial.